Modification of crystal anisotropy and enhancement of magnetic moment of Co-doped SnO2 thin films annealed under magnetic field

• Published in: Nanoscale research letters 2014-11, Vol.9 (1), p.635-635, Article 635
• Main Authors: Loya-Mancilla, Sagrario M, Poddar, Pankaj, Das, Raja, Ponce, Hilda E Esparza, Templeton-Olivares, Ivan L, Solis-Canto, Oscar O, Ornelas-Gutierrez, Carlos E, Espinosa-Magaña, Francisco, Olive-Méndez, Sion F
• Format: Article
• Language: English
• Subjects: Chemistry and Materials Science; Materials Science; Molecular Medicine; Nano Express; Nanochemistry; Nanoscale Science and Technology; Nanotechnology; Nanotechnology and Microengineering
• ISSN: 1931-7573; 1556-276X; 1556-276X
• DOI: 10.1186/1556-276X-9-635

Co-doped SnO 2 thin films were grown by sputtering technique on SiO 2 /Si(001) substrates at room temperature, and then, thermal treatments with and without an applied magnetic field (H TT ) were performed in vacuum at 600°C for 20 min. H TT was applied parallel and perpendicular to the substrate surface. Magnetic M(H) measurements reveal the coexistence of a strong antiferromagnetic (AFM) signal and a ferromagnetic (FM) component. The AFM component has a Néel temperature higher than room temperature, the spin axis lies parallel to the substrate surface, and the highest magnetic moment m =7 μ B /Co at. is obtained when H TT is applied parallel to the substrate surface. Our results show an enhancement of FM moment per Co +2 from 0.06 to 0.42 μ B /Co at. for the sample on which H TT was applied perpendicular to the surface. The FM order is attributed to the coupling of Co +2 ions through electrons trapped at the site of oxygen vacancies, as described by the bound magnetic polaron model. Our results suggest that FM order is aligned along [101] direction of Co-doped SnO 2 nanocrystals, which is proposed to be the easy magnetization axis.